The TRGB-SBF Project. II. Resolving the Virgo Cluster with JWST

TL;DR

This paper uses JWST observations to measure distances to Virgo Cluster galaxies via TRGB and SBF methods, aiming to refine the extragalactic distance scale and investigate the Hubble tension independently of Cepheid-based methods.

Contribution

It presents new JWST/NIRCam measurements of TRGB and SBF for Virgo galaxies, improving distance estimates and developing an independent Population II distance scale.

Findings

Determined Virgo Cluster distance as 16.17 Mpc with improved accuracy.

Adjusted previous SBF measurements using new TRGB data.

Supports the potential to resolve the Hubble tension through independent distance measurements.

Abstract

The Virgo Cluster is the nearest substantial cluster of galaxies to the Milky Way and a cornerstone of the extragalactic distance scale. Here, we present JWST/NIRCam observations that simultaneously cover the cores and halos of ten galaxies in and around the Virgo Cluster and are designed to perform simultaneous measurements of the tip of the red giant branch (TRGB) and surface brightness fluctuations (SBF). Seven of the targets are within the Virgo Cluster and where we are able to resolve some of the cluster's substructure, while an additional three provide important constraints on Virgo infall. The seven galaxies within Virgo itself all have SBF measurements from the Advanced Camera for Surveys Virgo Cluster Survey (ACSVCS). After adjusting the ACSVCS measurements for the offset from our new JWST TRGB measurements, we determine a distance to the Virgo Cluster of d $=$ 16.17 $\pm$ 0.25 (stat) $\pm$ 0.47 (sys) Mpc. The work presented here is part of a larger program to develop a Population II distance scale through the TRGB and SBF that is completely independent of the prominent Cepheid + Type Ia supernova ladder. The TRGB distances to the galaxies presented here, when combined with future SBF measurements, will provide a crucial step forward for determining whether or not systematic errors can explain the well-known "Hubble tension'' or if there is significant evidence for cracks in the $\Lambda$CDM model.